This post has been running prominently for over 3 weeks and not one person has indicated that they own a bike in the 6.5kg range and posted pictures of their lightweight steed. skyfire1202 is mentioned but he is no longer a member. Do they, owners/bikes, exist? This is weight weenies. In the road section loads of members claim to have 5kg road bikes.

It would be hard to build a first hand 6.5kg MTB for less than 10GBP/14USD/12EUR. As MTB bikes tend to take a hammering do people not bother for fear of seeing their 10GBP investment being wrapped around a tree. I ride my 5KG road bike hard but I'm very careful not to crash. I don't take risks on it.

Is that the reason why there does not appear to be any very light MTBs out there, or is there another reason, or are there just lots of shy or disinterested members out there?

Who's no longer a member? That is just one of my bikes. I built the bike for a hill climb race that we have here twice in a year. The 911-gram wheels are with sub220-gr Innolite rims, Tune Dezibel and Princess Skyline hubs laced with Superspokes and I have tested them on 1 foot jumps with no pronblems. It's with Eclipse tubes, but can be lighter with tubeless setup. I could change the wheels to Race Kings 2.2 and it would still be below 6Kg and it's plenty strong for my weight. I do have a DT XRC fork also custom painted for that bike just in case I need a front suspension, but I have a separate Scale RC hardtail setup with XX1 on Clavicula cranks too and sub 900-gram Extralite Tubotreme wheels mounted with XC2 Plus that is also sub 6.5Kg. For rougher races, I use my custom sub 7.1-Kg Spark 10 on XX1 setup with the same setup as the RC but with AX tubular rims and the rear spokes are CX-rays.

Sorry skyfire1202 but I looked you up under 'members' and couldn't find you.

LeDuke what you say makes sense and actually confirms my reasoning. Having said that if your pockets are deep enough I'm convinced, as skyfire1202 indicates, it is possible to build a 'strong as you like' trail 29er MTB under 7kg. A bike you could race all day long. To get to 6.5kg you will have to compromise on wheels and fork I would think.

It seems WW is for road users now, and only a bit for MTB. Things have changed in amateur cycling a lot over the last 10 years or so. Road cycling has eclipsed off road by a huge amount. I suppose the state of the MTB forum is just a reflection of that. You could blame Dave Brailsford.

I think skyfire1202 is still a member here. His bike 12.32lbs / 5.58kg

Sure, some people wouldn't think Maxlites etc are daily riders but skyfire1202 still races his bikes. It's not like it would be heavy with with a SID, Crest wheelset, Racing Ralphs and Ashima rotors anyway.

I'm planning on building a super light MTB but will I be wasting my money and ending up with something that has more disadvantages than advantages?

... but putting together a super light MTB that is robust enough to ride any any half decent rails is certainly a challenge and not done on a small budget. I work on the basis of "don't race what you can't replace" so if you are able to fold several thousand pounds worth of MTB exotica in a crash without crying then go for it

Plus you have said you plan to ride the MTB once a week so is the high cost justified? Only you can say. WW for me is all about the mentality and approach when building up a bike to suit your needs and each person will be restricted in some way by other factors such as durability/ value/ whatever. The WW mentality within your own constraints is more the WW spirit than absolute weight IMO so it isn't fair to say WW MTB is dead now...

As others have said, your best bet is to post up the parts you consider suitable for your build and others will be able to suggest alternatives one way or another.

If you're new to mountain biking then you'll find a bike of that weight harder to ride than something a bit heavier. The Surrey Hills aren't particularly technical, but you'll find yourself being bounced around all over the place on a bike of that ilk. It's not an inherent problem, but I'd suggest most people will go faster if you sacrifice weight for strength and stiffness in a few places.

I'm a surrey hills local, gladly show you around when you've built it!

Basically it depends if you want a bike to hang on scales, or one to ride.

Another thing is the hate that comes from members who have never seen <1000g wheel set never mind owned one and so on.

Some frames, wheels and forks were not stiff enough in 26'' size for bigger riders, yet they are perfect in 29'' format, regardless of some "improvements''

Chris.

Would love to own a <1000g wheelset. Had a wheelset for my Scalpel last year at 1002g, was stiff and good. The thing with light parts is that they need more care and most people only have one bike which makes i a bit harder. If you got two or more bikes it's easier to just save every gram you dare on one bike and keep it top notch.

For sure. The crazy thing about that bike is that it's already so light, but there are a few places to save weight, albeit not cheaply, but easily none the less and without cost in performance. Innolite rims or something similar, 1 piece carbon bar/stem/steerer combo, saddle combo, lighter crank/ring setup with maybe a single front chainring... etc

It seems WW is for road users now, and only a bit for MTB. Things have changed in amateur cycling a lot over the last 10 years or so. Road cycling has eclipsed off road by a huge amount. I suppose the state of the MTB forum is just a reflection of that. You could blame Dave Brailsford.

I think you miss the point too - mountain biking has evolved to a point where folk don't care about weight as much. Most people ride mountain bikes for the descents, where the best kit is rarely the absolute lightest. Look at the advances in mountain bikes: hydraulic brakes, suspension, 29ers, latterly things like dropper seatposts. All add weight, but for most they enhance the enjoyment.

Race courses are becoming more demanding at the same time, a rigid v-brake equipped bike may be the lightest, but it won't be the fastest.

There are some very active mountain bike forums - BikeRadar and Singletrackworld notably, but ultra lightweight kit really isn't of interest to the majority.

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